1. Field of the Invention
The present invention relates to a recombinant silk protein derived from sea anemones, a method for producing the same, and a composition for preparing a silk fiber including same.
2. Discussion of Related Art
Natural silk protein materials have been used as general materials for clothes for a long period of time, and may also be used as next-generation highly functional industrial materials because natural silk proteins have good biocompatibility, superior elasticity, and physical strength, and are capable of being formed into various forms such as powder, a membrane, a porous body, or gel, and can be chemically modified from natural proteins.
It known that the silk proteins have so far mainly been produced by silkworms and spiders.
In the case of silkworm silk protein, conventional production of textiles in which silkworms can be raised and 5 kg of silk protein can be produced from about 1,500,000 of silkworms in an area of 300 m2 has been widely used. Further, the natural silkworm silk protein may be used for cosmetic materials, an enzyme immobilization support, materials for cell cultures, or industrial materials such as artificial skin, because it is a human-friendly material which does not cause immunoreaction or allergic reaction. However, there is a minor limitation in using the silkworm silk protein for industrial materials because it has insufficient durability, that is, strength. Thus, various studies aimed at improving physical properties of the silkworm silk protein is underway. For example, there is research aimed at separating silk fibroin, a major component of silkworm silk protein, based on molecular weight, and a function thereof, research into preparation of a fine body of silkworm silk protein and skin affinity thereof, research aimed at improving physical properties through blending of a silkworm silk protein and a chemical synthetic polymer, and research into mixing a silkworm silk protein and a natural glucose-based polymer compound.
In the case of spider silk protein, since natural spider silk protein was found to have very good physical properties such as durability and elasticity, research into using the spider silk protein as industrial materials has been performed actively. However, it is known that it is impossible to raise spiders because they eat each other, and it is impossible to separate and produce natural silk protein like silkworm silk protein because the amount of silk protein produced from spiders is very small. Therefore, much research into spider silk protein has focused on introducing genes of the spider silk protein to various protein expression systems to produce a recombinant protein, and much effort has been attempted to perform mass production of a spider silk protein in E-coli, yeast, plant cells, animal cells, a gene-transplanted animal, or the like. On the whole, due to intensive research and investment since 2000, research into spider silk protein has recently begun to bear fruit, but genes of spider silk protein include repeated DNA sequences and repeated specific amino acid sequences such as glycine, alanine, or serine, which results in difficulty in producing natural silk protein materials by recombination. Even when the spider silk protein whose specific sequence is only partially expressed is mass produced, the produced material may be made into the form of yarn, but the physical properties are largely insufficient compared to those of natural spider silk protein.
Therefore, based on an understanding of the generic properties and physical properties of natural silkworm and spider silk protein, methods for mass production of a protein with such sequence features have been studied. Further, much effort has been made to search for new natural silk protein materials and secure an original patent thereof. From such a viewpoint, it is reported that ant and bee silk proteins have gene sequence features similar to silkworm or spider silk protein, and new silk protein materials in which genes with properties of a natural silk protein are redesigned are being designed.
Meanwhile, sea anemone is the general name of an animal of order Actiniaria which belongs in Cnidaria, phylum Cnidaria, class Anthozoa. Some sea anemones may dwell in the sea and attach to reef, but others may dwell in the sand or move using a pedal disc. Further, the sea anemone may float through a pedal disc having a column shape or swim by moving its body or tentacles. The sea anemone may eat floating planktons or even a larger fish. The sea anemone captures prey using many cnidocytes on tentacles in which toxic materials such as tetramin are discharged. Types of sea anemone include red rock anemone, coral anemone, or the like. The body includes an open mouth in the middle and several tentacles which are flexible muscle, cylindrical, and hollow. The body has a length of 1.5 to 5 cm and various widths. The color of the body is white, green, blue, orange, red, or the like. Most sea anemones are dioecious and reproduce sexually. Also, most sea anemones have external fertilization, but some species are ovoviviparous. Up to now, about 1,000 species of the sea anemone are known worldwide, and they each dwell independently without forming a colony, which is characteristically different from other animals that belong to class Anthozoa.
Species dwelling in the sea have not been investigated on the level of genes and proteins, and thus research into production of silk protein from these species has been almost non-existent. Therefore, when a method of producing a recombinant silk protein from many sea anemones dwelling in the sea is studied, it is thought that the recombinant silk protein may be substituted for silk protein derived from spiders and silkworms in the related art. Therefore, there is need for development of a recombinant silk protein derived from sea anemones.